From: David Ahern <dsahern@gmail.com>
To: Lorenzo Colitti <lorenzo@google.com>,
David Ahern <dsa@cumulusnetworks.com>
Cc: "Hangbin Liu" <liuhangbin@gmail.com>,
"David Miller" <davem@davemloft.net>,
"Yaro Slav" <yaro330@gmail.com>,
"Thomas Haller" <thaller@redhat.com>,
"Alistair Strachan" <astrachan@google.com>,
"Greg KH" <greg@kroah.com>,
"Linux NetDev" <netdev@vger.kernel.org>,
"Mateusz Bajorski" <mateusz.bajorski@nokia.com>,
"Maciej Żenczykowski" <zenczykowski@gmail.com>
Subject: Re: [PATCH net] fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied
Date: Wed, 5 Jun 2019 09:33:19 -0600 [thread overview]
Message-ID: <d8022629-0359-34b7-ccae-bb12b190e43b@gmail.com> (raw)
In-Reply-To: <CAKD1Yr30Wj+Kk-ao2tFLU5apNjAVNYKeYJ+jZsb=5HTtd3+5-Q@mail.gmail.com>
On 6/4/19 10:58 PM, Lorenzo Colitti wrote:
> As for making this change in 5.3: we might be able to structure the
> code differently in a future Android release, assuming the same
> userspace code can work on kernels back to 4.4 (not sure it can, since
> the semantics changed in 4.8). But even if we can fix this in Android,
> this change is still breaking compatibility with existing other
> userspace code. Are there concrete performance optimizations that
> you'd like to make that can't be made unless you change the semantics
> here? Are those optimizations worth breaking the backwards
> compatibility guarantees for?
The list of fib rules is walked looking for a match. more rules = more
overhead. Given the flexibility of the rules, I have not come up with
any changes that have a real improvement in that overhead. VRF, which
uses policy routing, was changed to have a single l3mdev rule for all
VRFs for this reason.
next prev parent reply other threads:[~2019-06-05 15:33 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-07 9:11 [PATCH net] fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied Hangbin Liu
2019-05-08 16:35 ` David Miller
2019-06-01 1:43 ` Maciej Żenczykowski
2019-06-01 9:32 ` Greg KH
2019-06-05 1:43 ` Hangbin Liu
2019-06-05 1:47 ` Lorenzo Colitti
2019-06-05 2:15 ` Hangbin Liu
2019-06-05 2:25 ` Lorenzo Colitti
2019-06-05 3:29 ` Hangbin Liu
2019-06-05 3:43 ` Lorenzo Colitti
2019-06-05 4:05 ` Hangbin Liu
2019-06-05 3:57 ` David Ahern
2019-06-05 4:08 ` Hangbin Liu
2019-06-05 4:58 ` Lorenzo Colitti
2019-06-05 15:33 ` David Ahern [this message]
2019-06-06 23:01 ` Maciej Żenczykowski
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